Windows may not detect a hot plugged PCI Express card

Applies to: Windows Vista UltimateWindows Vista EnterpriseWindows Vista Home Basic

Symptoms


Consider the following scenario:

You have a Windows Vista or Windows 7 machine.
After you boot the machine, you hot plug a PCI Express card.
The PCI Express card may not be detected in Windows.  

In the event that the card is detected, you may experience issues communicating with the device. 

Cause


When the PCI Express card is hot plugged after the machine boots, Windows Vista and Windows 7 does not correctly apply the ACPI _HPP value to the device against the ACPI specification.  This can prevent the device from being detected properly.

Resolution


Ensure that the PCI Express Card is plugged into the machine prior to the operating system booting.